Function contextFromEvent

contextFromEvent(
    event: {
        get: <T>(key: string, fallback?: T) => T;
        getUser?: <T>() => T;
    },
    blueprint?: { get: <T>(key: string, fallback?: T) => T },
    extra?: ResourceContext,
): ResourceContext
Build a ResourceContext from an incoming event.

The parameter names are configuration, not convention: an API that already answers ?view= or ?only= keeps its own vocabulary instead of gaining a second one. Defaults are fields, include and view.

The authenticated principal is read too, because deciding what a caller may see is the most common reason two callers get different shapes — and a resource that cannot see who is asking has to be told by the handler, which is exactly the plumbing this module exists to remove.

Agnostic: the event only needs get(key).
Parameters
- event: { get: <T>(key: string, fallback?: T) => T; getUser?: <T>() => T }
  Anything with get(key) (an IncomingHttpEvent, a URL search wrapper, …).
- Optionalblueprint: { get: <T>(key: string, fallback?: T) => T }
  The blueprint carrying the parameter names, when there is one.
- extra: ResourceContext = {}
  Extra context to merge in.
Returns ResourceContext
The resource context.